Preheat oven to 375,Mix brown sugar, minced garlic, and chicken broth together in separate bowl and set aside,Put onion, jalapenos, and chicken breasts in round or square pan that is at least 2 inches deep,______,Make small slices in the chicken breasts so the sauce will get in there real good,Pour brown sugar mixture over chicken,Bake for 45-50 minutes, turning chicken over about halfway through,Use the sauce from the pan to pour over the chicken if you want extra flavor and juiciness